Explosively actuated punch



"M 9 TEMPLE, JR 2,276,259

EXPLOSIVELY ACTUAT ED PUNCH Filed od. 12. 1959 has K4 ATTORNEYS.

Patented Mar. 10, 1942 UNITED STATES PATENT OFFICE EXPLOSIVELY ACTUATED PUNCH Robert Temple, Jr., Pittsburgh, Pa. Application October 12, 1939, Serial No. 299,116

9 Claims.

This invention relates to methods and apparatus for punching holes in relatively heavy members such as steel girders, plates and the like. More particularly, it is concerned with methods and apparatus of this type adapted to employ a detonated explosive charge for driving the punching means.

Heretofore, in structural steel and similar work it is often necessary to drill holes in I-beams, channels, steel Plates and the like. The usual procedure has been to employ an electric drill to provide the required hole. This operation is tedious, time-consuming and expensive and entails considerable hard labor on the part of the driller. It has not been practicable heretofore to provide punching apparatus to produce the necessary holes because of the size, weight and permanent character of ordinary punching apparatus.

It is a general object of my invention to provide relatively light, easily operated. and inexpensive portable apparatus which can be utilized to almost instantaneously punch holes in steel plates and the like.

Another object of my invention is the provision of an explosively actuated punch of the frame type which can be quickly and inexpensively used to punch straight sided holes in a girder, plate and the like.

Other objects of my invention are to Provide an improved method for punching holes in steel plates or the like by the use or a detonated explosive charge and a method whereby the punch can be readily withdrawn from the material punched.

Another object of my invention is the provi-- sion of punch removing apparatus for facilitating withdrawal of a punch from the material punched.

The foregoing and other objects of my invention are achieved by that method of punching a hole in a steel plate or the like which includes the steps of supporting the plate on a die, clamping a barrel against the plate to hold it on the die, and shooting a punch through the barrel and against the plate under the force of a detonated explosive charge. The punch is removed by securing a rod to the punch through the barrel, and pounding on the rod to withdraw the punch.

My improved apparatus comprises a C-frame, a die removably received in one leg of the C- trame and having a lateral opening for the removal of the punched-out material, a barrel extending through the other leg of the c-irame and in alignment with the die, means adjustably mounting the barrel in the c-frame for movement toward and from the die, a punch slidably received in the barrel, a breech member adapted to receive; an explosive charge. and removably secured on the barrel remote from the die. a

breech block and firing mechanism removably secured over the end of the breech member, and means on the punch engaging frictionally with the breech member and normally holding the giunch at the end of the barrel remote from the It is a part of my advance in the art to provide punch withdrawing apparatu comprising a rod which is adapted to be secured to the end of the punch. The rod is formed with a stop and with a slidably mounted weight so that by hammering the weight against the stop the punch can be withdrawn from the work.

For a better understanding of my invention reference should be had to the accompanying drawing wherein Fig. 1 is a side elevation partly in vertical section of one embodiment of my improved punch; Fig. 2 is a vertical cross-sectional view taken on the line IIII of Fig. 1 and further illustrating the punch-removing apparatus in operating position; and Fig. 3 is a fragmentary vertical sectional view or a modification of my invention.

In the form or my vention illustrated in Figs. 1 and 2 of the drawing, the numeral It) indicates, as a whole, a C-frame formed of strong shockresistingalloy tions I2 and M which are ordinarily of somewhat greater-thickness than the main body flange it of the C-frame Ill. The leg i2 of the C-frame is recessed and removably receives a die l8 which may be held in place in any known manner, as for example, by a set screw 20. The leg I 2 may be provided with an aperture 22 in alignment with the die l8 which facilitates removal of the die [8 by punching a rod up through the aperture 22. The die I8 is formed with a central chamber 24 of larger diameter than the die opening proper and the chamber 24 i extended through the side of the die into communication with a lateral opening 26 in the side of the leg I2. The die i8 is also formed with a smaller lateral opening 28 which communicates with the chamber 24 and with a lateral opening an in the side of the leg l2 so that a rod can be pushed through the openings 28 and 30 to knock out the plug P of material punched out of the plate or sheet S of material being operated on.

The leg I4 or the c-frame i0 is formed with a bore which adjustably receives a barrel 36 so steel and having opposed leg porthat it is in alignment with the die l6. Athr ed connection 36 between the barrel and the leg I allows the barrel to be moved into and out of the leg it so as to clamp the sheet 8 of material being operated on against the die l8. Handles 46 secured to the barrel 36 facilitate adjustment of the barrel with respect to the leg ll of the c-irame. A breech member 42 is secured to the end of the bar'rel 36 and this may be conveniently done by providing complementary threaded portions 44. The breech member 42 is formed with a breech opening 66which receives a. charge of explosive material which is conveniently in the form of a blank cartridge 48, as illustrated in Fig. 1. The end of the breech member adjacent the charge-receiving chamber 66 is surrounded by an ejector cap 56 which is secured by a coarse thread 52 to the breech member. The end or the ejector cap 56 is suitably recessed so as to receive the primer portion of the blank cartridge 66.

A breech block 56 is re'movably secured over the end of the breech member 42 by complementary threads 58 and the breech member is provided with an axially disposed firing pin 66 mounted for limited movement toward and from the breech \member. A convenient way of mounting the firing pin 66 includes the provision of a collar 62 which surrounds the stem or the firing pin and is threaded into the end or the breech block in the manner shown. A set screw 64 locks the collar 62 in position.

The breech member 42 clamps a centrally apertured plug i6 against the end otthe barrel 36 and the plug is formed with a circular boss 12 which extends into the end of the barrel. A punch 14 is slidably received in the barrel 66 and is provided with two or more spring fingers 16 which are preferably formed integral with the end of the punch and which engage Irictionally with the boss '82 to normally retain the punch M at the breech end of the barrel 36. The work performing end of the punch 14 is of reduced diameter as shown. Usually the reduced end portion is formed with a substantially cylindrical part 86 and an outwardly tapered cutting part 62. I may make the punch 24 from a single piece of tool steel but I may also form the body of the punch M which engages with the inside of the barrel 36 of one piece of material and form the portions 86 and 82 of separate pieces or steel which are secured to the main body as by a screw connection. The extreme end 01' the portion 62 c; the punch 14 is formed with a centering nipple 64 which is adapted to engage with a center punched hole in the sheet 8 of material being worked on. This facilitates the alignment of the tool with the work.

An important part of my invention is the provision of means for facilitating the removal or withdrawal of the punch from the work after the punching operation. To this end. I form the breech end of the punch ll with a threaded recess 96 which is adapted to receive the threaded end of a rod 92 which is extended through the breech member 62 and the barrel 36 in the manner shown in Fig. 2 of the drawing. The rod 92 is formed with a stop or shoulder 96 substantially at the point indicated in the drawing and is provided at its upper end with a knob 96. A relatively heavy weight 98 generally of circular configuration is slidably mounted on the rod 92 between the stop 94 and the knob 96. r

In the operation of my improved plmching apparatus the work 3 is first center punched 36 in a retracted position. The punch M is allowed to drop down to center the nipple 66 in the center punched hole and then the handles 66 are turned to move the barrel 36 down tightly against the work S to clamp it in proper position against the die 18. Thereafter, the punch M is moved back by the rod 92 to bring the fingers 16 into frictional engagement with the boss 12. The rod 92 is then unthreaded from the punch 14 by turning the knob 96 and the rod is removed. A blank cartridge 68 is then placed in the breech aperture 46 and the breech block 56 is turned down on the breech member 42 to the position shown in Fig. 1. The apparatus is now ready to be fired which can be readily accomplished by striking the firing pin 66 with a suitable mallet or hammer. Uponthe detonation of the blankcartridge 46, the'punch I4 is held back towards the breech end of the barrel 36 until the force of the detonated powder charge is sufilcient to overcome the friction between the spring fingers l6 and the boss 12. Thereupon the punch is driven with high speed and great force through the barrel to punch out the desired hole in the work 8. The plug P punched out by the tool is received in the chamber 24 in the die l6 and is removed by pushing the end of the rod 92 through the side openings 86 and 26 to discharge the plug through the openings 26 and 26.

The breech block 56 is then removed and the ejector cap 56 is turned to eject the blank cartridge shell from the breech member 62. The rod 92 is then inserted through the breech member and into the barrel 36 and its threaded end is turned into engagement with the recess 96 at the breech end of the punch 14. The operator then grasps the weight 96 in his hand and by pounding it up against the knob 96 drives the rod 92 and the punch 16 towards the breech end of the barrel and thus withdraws the punch 16 from the work. An alternative manner of removing the punch from the work comprises connecting the rod 92 with the punch 14 as before and then turning the barrel 36 by way of handles 46 outwardly in the frame ID to bring the ejector cap 56 into engagement with the shoulder 96. Continued rotation of the barrel 36 to move it outwardly of the frame pulls the punch from the work. After the removal of the punch the apparatus can be operated to perform a second punching operation in the manner already described.

The modification of my invention shown in Fig. 3 of the drawing includes a C-frame l6a having opposed leg portions l2a and Ma. The leg Ma adjustably receives abarrel 360 which carries an arresting ring I66 at its muzzle end. The ring I66 is either pressed or threaded into a suitable counterbore I62 in the barrel. From the drawing it will be seen that the ring I66 has a central opening which allows the reduced end 92a of the punch "a to pass through it but that the body of the ring engages with the main body of the punch to limit its forward movement in the barrel.

The leg I201 01 the C-frame l6a removably receives a ring die I641 in an axial counterbore and and is then placed on the die l6 with the barrel the die may be locked in position by a set screw 260. An axially aligned opening 22a terminating in a lateral opening 36a receives the slug or plug punched out from the material worked on and facilitates the removal of the plug.

The operation of this embodiment of my invention is similar to that already described. However, in the apparatus of Fig. 3 the punch 14a is stopped in the barrel 36a by the arresting ring I and is not stopped by crushing the plug P against the bottom of the chamber 24 as is the case in the apparatus of Figs. 1 and 2. Removal of the plug P and the simplification of the die L8 is facilitated in the apparatus of Fig. 3.

From the foregoing it will be recognized that the objects of my invention have been achieved by the provision of an improved apparatus ofa relatively light weight, completely portable nature for rapidly and efliciently punching holes in metal sheets, plates, girders and the like. The, apparatus can be readily operated by the ordinary workman to almost instantaneously perform a desired operation. Furthermore, the removal or withdrawal of the punch from the work is facilitated and adds little or no time to the punching operation.

By changing the size of the die l8 and the size of the punch H the tool can be adapted to punch holes of any desired size and character.

Likewise, the punch and die can be formed to punch a hole of substantially any shape, round or otherwise. It is of interest to note that holes punched with my improved apparatus are straight sided. Even in punching operations on relatively heavy material there is a definite tendency to form a tapered hole which is often objectionable. However, I have found that my apparatus produces holes of substantially the same diameter completely through the thickness of the metal being worked. I believe this result is due to the fact that the punch is driven through the work at such a high velocity and with such momentum that there is little or no chance for the metal radially outwardly of the sides of the cutting edge of the punch to be deformed particularly when the metal is backed by a die having an aperture therethrough of a diameter only several thousandths of an inch greater than the diameter of the punch itself. This arrangement of parts is of course provided in my apparatus.

While in accordance with the patent statutes I have particularly illustrated and described my invention, it will be understood that I am not to be limited thereto or thereby but that the scope of my invention is defined in the appended claims.

I claim:

.1. That method of punching a hole in a steel plate or the like which comprises center punching the plate, supporting the plate on a die, aligning a barrel with the center punch on the plate, clamping the barrel against the plate to hold it on the die, shooting a punch through the barrel and against the plate under the force of a detonated explosive charge to punch a hole in the plate, securing a rod to the punch through the barrel, and pounding on the rod to withdraw the punch.

2. That method of punching a hole in a steel plate or the like which comprises supporting the plate on a die, clamping a barrel against the plate to hold it on the die, shooting a punch through the barrel and against the plate under the force of a detonated explosive charge, securing a rod to the punch through the barrel, and pounding on the rod to withdraw the punch.

3. An explosively actuated tool for punching holes and the like comprising a c-frame, a die removably received in one leg of the C-frame, a barrel extending through the other leg of the c-irame and in alignment with the die, means adjustably mounting the barrel in the C-frame for movement toward and from work thereon, a punch slidably received in the barrel, a breech member adapted to receive an explosive charge and associated with the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end 0! the breech member, and means on the punch engaging frictionally with the breech member and normally holding the punch at the end of the barrel remote from the die.

4. An explosively actuated tool for punching holes and the like comprising a C-frame, a die removably received in one leg of the O-frame, said die having a lateral opening for the removal of punched out material, a barrel extending through the otherleg of the C-irame and in- 'alignment with the die, means adjustably mounting the barrel inrthe C-frame for movement to-..

ward and from the die to clamp work thereagainst, a punch slidably received in the barrel, a breech member adapted to receive an explosive charge and removably secured on the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end of the breech member, and means on the punch engaging .frictionally with the breech member and normally holding the punch at the end of the barrel remote from the die.

5. An explosively actuated tool for punching holes and the like comprising a c-frame, a ring die removably received in one leg of the C-frame, a barrel extending through the other leg or the c-irame and in alignment with the die, means amustably mounting the barrel in the c-frame for movement toward and from the die to clamp work thereagainst, a punch slidably received in the barrel, 9. breech member adapted to receive an explosive charge and removably secured on the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end of the breech member, and an arresting ring at the end of the barrel for limiting the movement of the punch through the barrel.

6. An explosively actuated tool for punching holes and the like comprising a c-frame, a die in one leg of the C-frame, a barrel extending through the other leg of the C-frame and in alignment with the die, means adjustably mounting the barrel in the c-i'rame for movement toward and from the die, a punch slidably received in the barrel, a breech member adapted to receive an explosive charge and associated with the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end of the breech member, and hammer means comprising a rod having a sliding weight thereon and adapted to be secured to the punch through the breech member to facilitate the withdrawal of the punch from the material punched. I

7. An explosively actuated tool for punching holes and the like comprising a C-irame, a die in one leg of the c-i'rame, a barrel extending through the other leg 01' the c-frame and in alignment with the die, means adjustably mounting the barrel in the C-frame for movement toward and from the die, a punch slidably received in the barrel, a breech member adapted to receive an explosive charge and associated with the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end 01 the breech member, and hammer means adapted to be secured to the the die to clamp 76 punch through the breech member to facilitate the withdrawal of the punch from the material punched;

8. An'explosively'actuated tool for punching hoiesrand the like comprising a G-frame, a die removably received in one leg of the O-frame. said die having a lateral opening for the removal of punched out material, a barrel extending through the other leg .of the C-frame and in alignment with the die, mean adjustably mountin; the barrel in the c-frame for movement toward and from the die, a. punch slidably received in the barrel, -a breech member adapted to receive an explosive charge and removably secured on the end of the barrel remote from the die, a breech block and firing mechanism removably secured over the end of the breech member, means on the punch engaging frictionally wlth the breech member and normally holding the punch at the end of the barrel remote from curedto the punch through the breech member the die, and hammerfmeans adapted to be se- 20 to facilitate the withdrawal of the P ch from the material punched.

9. an explosively actuated tool for punching helm and the like comprising a frame, a work support on the frame, a barrel extending through the frame and in alignment with the work support. a punch slidably received in the barrel, a breech member adapted to receive an explosive charge andassociated with the end of the barrel remote from the work support, a breech bloc and firing mechanism removably secured over the end of the breech member, a rod adapted to be removably secured to the punch through the breech member, spaced SfDps on the rod, and a sliding weight on the rod between the stops which can be hammered against the stops to facilitate the withdrawal of the punch from the material pimched.

ROBERT TEMPLE, Ja. 

